Comparison of Body Mass Index and Metabolic Score for Visceral Adiposity in Evaluation of Visceral Adiposity

Overview

Visceral obesity is a major risk factor for cardiometabolic diseases such as type 2 diabetes, hypertension, and coronary artery disease. In clinical settings and during research, "body mass index (BMI)" is usually used for assessing obesity, and when it is above 30 kg/m2, it is defined as obesity. However, the risk posed by obesity is more related to body fat distribution than total body fat, and BMI only reflects the second. Individuals with a BMI below 30, even 25, may still have visceral adiposity detectable via an abdominal computerized tomography ( CT) or magnetic resonance imaging (MRI). Therefore new, practical, inexpensive parameters are needed to evaluate visceral adiposity. "Metabolic Score for Visceral Adiposity (METS-VF)", "Body Shape Index (BSI)", "Conicity Index (CI)" and "Body Roundness Index (BRI)" are a few recent indexes developed trying to fulfill these needs. The aim is to investigate the effectivity of METS-VF in comparison with BMI, BSI, CI, and BRI in reflecting visceral adiposity assessed with CT.

This study is a single-center, observational and prospective study. Patients who underwent abdominal computed tomography (CT) covering the L3-L4 level in the last month for any reason and who did not have any of the following situations in the participants' CT reports: malignancy, pancreatitis, diseases requiring further investigation, chronic inflammatory diseases, and a pathology requiring hospitalization for more than 24 hours, will be invited to the study. Of the patients who consent to the study, gender, age, education level, current diseases, medications, and smoking status are questioned. Anthropometric measurements, especially waist, height, and weight are taken. Patients' biochemical parameters such as lipid profiles (LDL-cholesterol, HDL-cholesterol, Triglyceride), urea, creatinine, uric acid, fasting blood glucose, and C-peptide levels (after 8-12 hours of fasting), and thyroid hormones were measured in the last three months are recorded from the participants' files. The body mass index (BMI) of the patients will be calculated with the formula weight (kg) / height (m)2. Patients will be in 5 groups with BMI \<25 kg/m2, 25-29.9 kg/m2, 30-34.9 kg/m2, 35-39.9 kg/m2, and \>40 kg/m2, with 40 patients in each group. Visceral adipose tissue will be calculated by the radiologist by measuring with the "slicer" method at the level of L3-4 on abdominal CT. For "Metabolic Score for Visceral Fat (METS-VF)", the formula 4.466 + 0.011\*(Ln(METS-IR))3 + 3.239\*(Ln(Waist/height ratio))3 + 0.319\*(Gender) + 0.594\*(Ln(Age)) and for "Body Waist Circumference" the formula (BMI2/3 \* height1/2) are used. Based on the visceral adipose tissue measured by CT, firstly, BMI and METS-VF will be compared, and then the other mentioned anthropometric index values will be compared statistically. The assumption is that the METS-VF index is superior to the other indexes, including the BMI. Also, as a second endpoint, it is aimed to find a cut-off value for METS-VF in Turkish individuals to reflect the increased visceral adiposity assessed with CT.